md: avoid array overflow with bad v1.x metadata
We trust the 'desc_nr' field in v1.x metadata enough to use it
as an index in an array. This isn't really safe.
So range-check the value first.
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index c194955..249b289 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1308,7 +1308,12 @@
}
if (mddev->level != LEVEL_MULTIPATH) {
int role;
- role = le16_to_cpu(sb->dev_roles[rdev->desc_nr]);
+ if (rdev->desc_nr < 0 ||
+ rdev->desc_nr >= le32_to_cpu(sb->max_dev)) {
+ role = 0xffff;
+ rdev->desc_nr = -1;
+ } else
+ role = le16_to_cpu(sb->dev_roles[rdev->desc_nr]);
switch(role) {
case 0xffff: /* spare */
break;